Tie-down rails are used with ropes, straps and bungee cords to constrain cargo on pick-up truck cargo boxes, station wagon roofs and van roof. Tie-down rails known in the art suffer from a number of disadvantages, such as manufacturing equipment investment costs, high inventory (parts in process and finished parts) costs, difficult-to-install procedures, and poor structural integrity. Many tie-down rails apply only to a single vehicle brand or model, requiring a manufacturer to maintain a large inventory of tie-down rails. This results in higher retail prices and/or reduced profits.
Some pick-up trucks have stake holes in cargo boxes for stakes that attach wooden rails. Although stakes and wooden rails are very seldom used, stake holes are convenient for attaching tie-down rails. Okland U.S. Pat. No. 5,476,349; Davenport U.S. Pat. No. 5,827,024; Bundy U.S. Pat. No. 5,904,458 and Rowe U.S. Pat. No. 6,176,658 are exemplary of pick-up truck rails in the prior art. Okland U.S. Pat. No. 5,476,349 discloses a pair of fixed length tubular tie-down rails with separate die cast ends mounted in stake holes. The die cast parts require expensive molds and fixed length rails are specific to a single vehicle brand or model.
Davenport U.S. Pat. No. 5,827,024 discloses a pair of one-piece fixed length tubular tie-down rails with bent ends. The rails have low bending stiffness and are applied to a single vehicle brand or model. Bundy U.S. Pat. No. 5,904,458 discloses a pair of rails mounted in drilled holes of a pick-up truck box. Rowe U.S. Pat. No. 6,176,658 discloses fixed length tie down rails bolted or welded to a pick-up truck box.